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Mathematics 8 Online
OpenStudy (jewlzme17):

Solve for x.

OpenStudy (jewlzme17):

OpenStudy (jewlzme17):

Now I think I know how to sort of do it. What I got is that I put it into 8x/5x+3=10x-2/7x and then I cross multiply and i get 56x^2 = 5x+3(10x-2) and now I think I use the FOIL method to distribut 5x+3 into 10x-2 and I then get 56x^2=10x^2+40x6...so do I have it good so far? What do i do next?

OpenStudy (jewlzme17):

What do you mean? Arent I supposed to use the Triangle- Angle - Bisector Theorem?

OpenStudy (yttrium):

Your solution is only true if the two triangles are proven to be similar.

OpenStudy (smored):

no, @jewlzme17 is right, that theorem works.

OpenStudy (jewlzme17):

thank you, okay so then did I do something wrong? and what am I supposed to do next?

OpenStudy (yttrium):

it's a quadratic equation! you know what it is @jewlzme17

OpenStudy (jewlzme17):

yes

OpenStudy (yttrium):

(5x+3)(10x-2) = 50x^2 +20x - 6 50x^2 +20x - 6 = 56x^12

OpenStudy (smored):

\[\frac{ 10x-2 }{ 7x }=\frac{ 8x }{ 5x+3 }\] so \[(10x-2)(5x+3)=(7x)(8x)\] \[50x ^{2}+20x-6=56x ^{2}\] \[-6x ^{2}+20x-6=0\]factor that to get \[(-3x+1)(2x-6)=0\]

OpenStudy (yttrium):

Then, 6x^2 - 20x +6 = 0 3x^2 - 10x + 3 = 0 (3x-1) (x-3) = 0 Hence x = 1/3 and 1

OpenStudy (smored):

1/3 and 3, according to my explanation

OpenStudy (jewlzme17):

okay so then that would be x?

OpenStudy (smored):

2 answers, x=1/3 for sure and I got x=3 for the other, though @Yttrium got x=1

OpenStudy (yttrium):

oh sorry. it's 3.

OpenStudy (smored):

Both of our explanations are right, tho different methods.

OpenStudy (yttrium):

it just implies that there are two possible solutions for x. it can be 1/3 or 3.

OpenStudy (jewlzme17):

oh okay! Thank you guys :)

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